The present invention relates to a mold for molding plastics, made of a nodular or spheroidal graphite cast iron.
In the art of molding or forming plastic materials, there have been used molds which are castings of various steel materials. Since a steel material generally undergoes a high degree of shrinkage when its melt is solidified, it is relatively difficult to cast steel molds with satisfactory dimensional accuracy. Further, the high shrinkage percentage of the steel material causes not a few cracks of such steel molds at their corner sections. Thus, such traditional cast steel molds for plastic molding are not completely satisfactory.